Many promising studies indicate that molecular imaging with ultrasound can rapidly and economically provide sensitive, high-resolution detection of vascular events, such as angiogenesis, inflammation and thrombus. Thus, Ultrasound molecular imaging has the potential to have a widespread impact in clinical medicine and biological research. Current non-contrast-assisted ultrasound lacks the specificity to detect molecular signatures of targeted disease events, such as angiogenesis. However, ultrasound has the advantages of low cost, portability, and dynamic imaging capability, and is already widely used for clinical diagnosis. Targeted contrast agents have been developed for ultrasound molecular imaging, but their immunogenic properties make them untranslatable to the clinic. Thus, improving the safety and enhancing the sensitivity of ultrasound molecular imaging will have a significant impact on the diagnosis and assessment of thrombus, inflammation, and cancer. Before ultrasound molecular imaging can be translated to the clinic, the immunogenic effects caused by the exposure of targeting ligands on the contrast agent surface must be reduced. We propose research studies to examine in detail the physicochemical mechanisms of immune response to ultrasound contrast agents, and we will use this data to design contrast agents which are shielded from this immune response. Simultaneously, we will study the ultrasound interaction with stealth agents that have been shown in preliminary data to be selectively activated by ultrasound radiation force. Collaboration with an ultrasound device manufacturer will allow the modification of a small-animal imaging system for specific optimization to work with the new stealth contrast agents for enhanced pre-clinical imaging. The end goal will be to develop safer ultrasound contrast agents which will also exhibit increased specificity and circulation time in-vivo, and to improve ultrasound scanner technology to take advantage of new, stealth contrast agents. PUBLIC HEALTH RELEVANCE: Ultrasound molecular imaging has the potential to have a widespread impact in clinical medicine and biological research. Before ultrasound molecular imaging can be translated to the clinic, the immunogenic effects caused by the exposure of targeting ligands on the contrast agent surface must be reduced. The project will develop safer targeted ultrasound contrast agents with decreased immunogenicity and increased specificity in vivo and improve ultrasound scanner technology to take advantage of the new contrast agents. [unreadable] [unreadable] [unreadable]